The sight of one man in the dock mesmerised the Arab world on Wednesday. Trade volumes on the Egyptian stock exchange hit a 10-year low, because traders could not take their eyes off the televised trial. For millions of Syrians, Yemenis and Libyans, all with dictators desperate to avoid the same fate, the courtroom drama from Cairo was just as relevant as it was to Egypt. Hosni Mubarak, who herded countless opponents into the caged dock, many to their deaths, was now in the same place himself.

But there the neat symbolism ends. Lying on a stretcher in standard-issue white prison overalls, Mubarak is being tried for only two days out of his 30-year rule on the charge of the killing of protesters in the January uprising. He is also accused of profiting from a gas deal with Israel and of other corruption charges, along with his two sons, Alaa and Gamal. But it is safe to say most evils of martial law, such as torture, will go unpunished. The thirst for retribution among his many victims is understandably strong, but establishing accountability comes first. Only a fair trial, transparently conducted, will constitute a clean break with the past.

Already, there are reasons to doubt whether such a trial will take place. The pre-trial period of investigation was short and the prosecutor's referral took place in under three months. Mubarak is 83 years old and unwell, although how unwell is a matter of debate. His lawyers have argued that he is unfit to attend trial. But the lack of transparency and the inconsistencies published over the state of his condition have led many to conclude that the Supreme Council of Armed Forces, which now runs the country, wants to shield one of their own. Other trials of Muburak-era ministers and officials leave much to be desired. Some have been adjourned. In others, the families of the victims have been approached for out-of-court settlements. There has been pressure on the families and a push back from army officers. Like everything else that takes place in a country midway through a transition to democracy, transitional justice is messy. In these turbulent conditions, there is an even heavier burden on Mubarak's trial to set the gold standard on how such justice is delivered.

The omens were mixed on the first day. Outside the courtroom there were running battles between police and rival mobs of pro-and anti-Mubarak protesters. Inside the court, the trial resembled at times a bazaar, with lawyers shouting over each other to get the judge's attention. One demanded a DNA test, claiming the man on the stretcher was an impostor. More seriously, the strategy of Mubarak's defence team became clear – to call over 1,000 witnesses to lengthen the trial proceedings as much as they could, and to frighten the ruling army council by hinting that Mohamed Hussein Tantawi, Mubarak's defence minister and the current de facto ruler of the country, could be called as a witness. This is going to be an extremely politicised criminal trial. But on the positive side, the judge selected has a good reputation and the proceedings were televised live. This allows less wriggle room for what the Russians know bitterly as "telephone law" – dictating the judgment to the judge. It will need all of the court's collective discipline and will to get the job done. This can not be done speedily, but nor can the trial be delayed or postponed.

Mubarak's trial is not just important for Egypt. Yemen's president, Ali Abdullah Saleh, injured in a rebel attack and getting medical treatment in Saudi Arabia, is being offered immunity form prosecution in a deal openly backed by a selective west. Tunisia's deposed president, Zine al-Abidine Ben Ali, was tried and sentenced in absentia. Again justice denied. If a deal were done with Libya's Muammar Gaddafi, it would be at the expense of charges for war crimes. It is no exaggeration to say that, along with elections, the democratic future of the Arab world depends on this trial.